SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db7de1057daa65422d949f2899e90d1478acf97c8f7301fa8f9069cfe38a6954' 
  AND token = 'QTM+NOqzoghtfvRzVGR+pDxnR025igCf2253W4G5Pow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}